The present invention relates to a method for the production of a cylinder sleeve, as well as to such a cylinder sleeve.
Cylinder sleeves for internal combustion engines are nowadays generally produced from cast iron with lamellar graphite as the material. The cast iron with lamellar graphite used for this purpose consists of the structural components pearlite and graphite, and is frequently alloyed with 0.1 to 1.2% phosphorus, in order to increase the wear resistance of this material. Wear on a cylinder sleeve is brought about, in engine operation, by the piston rings, on the one hand, and by the piston skirt, on the other hand, both of which interact with the inner mantle surface (or working surface) of the cylinder sleeve. By means of alloying in phosphorus, a phase that consists of iron, carbon, and phosphorus is formed in the material, which is referred to as steadite. This phase is distributed in net-like form around the eutectic cells of the cast iron, in the material structure, and is characterized by great hardness. As an alternative, elements that promote carbide formation to a great degree, for example niobium or boron, can be alloyed into the cast iron. This results in carbides that form a net-like structure similar to steadite. Furthermore, the pearlite contained in the cast iron contributes to great resistance to wear and seizing, since carbides in a lamellar structure are contained in pearlite.
For modern engines, particularly modern diesel engines, cylinder sleeves made from cast iron with lamellar graphite as a material are only suitable with restrictions. In particular, the ignition pressure required in modern diesel engines requires a switch to high-strength materials. These high-strength materials also include steel. In this connection, it is desirable to implement the structures of pearlite with carbides in a net-like structure known from the cast iron materials in the steels used for cylinder sleeves, in order to achieve good resistance to wear and seizing. This is not possible, however, since steels having a carbon content of more than 0.8 mass-% are required for this. Such steels are extremely difficult to form, because of their great hardness and strength, can only be welded with additional treatment, and can be worked using cutting methods only at great tool wear. The use of such steels is therefore excluded, because an unjustifiable amount of effort is connected with it.